Compliance with the Veterans Health Administration’s Pharmacy Benefit Management guidance for duration of clopidogrel following peripheral vascular interventions: a retrospective cohort study

BACKGROUND: Clopidogrel was added to the national formulary of the Veterans Health Administration (VHA) in 2000, with national guidance in the form of Criteria for Use (CFU) generated in 2007 by the Pharmacy Benefits Management office. Although the national CFU restricted the duration of clopidogrel to no more than 30 days following peripheral vascular intervention (PVI) for peripheral artery disease (PAD), each local VHA Veterans Affairs Medical Center (VAMC) determined its own strategies of implementation. Strategies ranged from passive diffusion of information to electronic health record-mandated pharmacist approval for noncompliant CFU prescribing. OBJECTIVE: To characterize patterns of compliance to restricted duration of clopidogrel and determine the factors associated with compliance. METHODS: In a retrospective cohort study, we used the Veterans Affairs Surgical Quality Initiative Program (2007-2022) to identify index PVI performed for PAD and integrated post-PVI medication information from the VA Clinical Data Warehouse. Our primary outcome was to evaluate compliance with the CFU. During the active CFU period (2007-2018), we compared patient, procedural, and VAMC features by CFU compliance and determined their associations with compliance using multivariable logistic regression. We also characterized variation in compliance across the Veterans Integrated Service Network (VISN), VAMC, and surgeons. RESULTS: Among 7,206 PVIs with postoperative clopidogrel, 35% and 26% had post-PVI clopidogrel durations of no more than 30 days during and after the CFU period, respectively. During the active CFU period, we found no strong association among patient, PVI, and VAMC characteristics with compliance. Compliance during the active CFU period varied significantly among VISNs (16%-55%), VAMCs (0%-93%), and surgeons (0%-100%). CONCLUSIONS: Adherence to no more than 30 days of clopidogrel post-PVI was low during and after the active CFU period and varied substantially among the VISNs, VAMCs, and surgeons. Given that national guidance implementation was directed by local VHA pharmacies, this study highlights the importance and limitations of local implementation strategies on national guidance compliance.